PSC 131 Lecture Notes - Lecture 2: Detection Theory, Psychophysics, Absolute Threshold
Document Summary
Lecture 2 measuring perception with psychophysics (april 4, 2017) Find absolute threshold for perception by increasing or decreasing intensity and ask subjects whether or not they perceive a stimulus: the probability of detection is gradual. *jnd is relative to context to original stimulus intensity: a change in weight must be 2. 5% of beginning weight to be noticed as different, a proportion of the original weight. 20lb bag jdn = 0. 5lbs; 2lb chocolate box jdn = 0. 05lbs (0. 8oz: other examples: How many in the other before you can tell that the two envelopes have different weights: adding another quarter (doubles weight, but, now imagine that those quarters are in your hiking boots. Imagine speaking to someone in the library vs a rock concert how much louder do you have to be in the concert? (think of the loudness of your voice as a fraction of the background noise. ) Jnd change detection needs to increase the absolute physical stimulus intensity.
